1. Field of the Invention
The invention relates to shingles and methods of applying shingles. More specifically, the invention relates to shingles configured to help reduce or nearly eliminate objectionable patterns.
2. Description of Related Art
Laminated shingles include at least two layers: a top layer that includes one or more tabs and one or more cut-outs, and a backing strip, or layer, positioned (e.g., disposed) under and often attached (e.g., by gluing) to the top layer. The current state of the art is to use top layers that have tabs that are less than seven inches in width. When these shingles are applied to a roof, the tab or tabs (and partial tab or partial tabs) from the top layers of the shingles can form objectionable, repeating patterns. Examples of these patterns include “striping” (e.g., “tiger striping” or “zebra striping”) and “zippering.” The term “vibration effects” has also been used to describe the impression these patterns give to the viewer.
Zippers may be straight or have one or more bends. An example of zippering is shown in FIG. 1. Some of the tabs and partial tabs that form the zippers in FIG. 1 are outlined. Zippering is usually magnified when the thickness of the tabs increases, or when the tabs cast shadows.
Stripes may be straight or curved. An example of striping is shown in FIG. 2. Striping is usually magnified when the thickness of the tabs increases, or when the tabs cast shadows.
Many attempts have been made to reduce objectionable patterning. One attempt involved the use of colored striations on shingle layers. See U.S. Pat. No. 5,611,186. Another attempt involved making shingles with random tab patterns. See U.S. Pat. No. 6,220,329.